Department of Stomatology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China.
Hubei Province Key Laboratory of Oral and Maxillofacial Development and Regeneration, Wuhan, China.
J Dent Res. 2020 Jun;99(6):713-720. doi: 10.1177/0022034520913248. Epub 2020 Mar 20.
Dental caries is a cariogenic bacteria-mediated, fermentable carbohydrate-driven dynamic disease. The new ecological hypothesis for dentin caries suggests that an alteration in the microbial community and the presence of specific metabolic pathway genes contribute to the initiation and progression of caries. This study aimed to determine the structural and functional characteristics of a microbial community of human deep-dentin carious lesions. Sixteen deep-dentin carious lesions were obtained from the first permanent molars of 8 patients aged 9 to 18 y. Shotgun metagenomic sequencing was used to measure the microbial composition and abundance at the phylum, class, order, family, genus, and species levels. Functional analysis of the DNA sequencing data set was also performed and compared among different layers of the lesions using DIAMOND software against the Kyoto Encyclopedia of Genes and Genomes database. This study found that in the deep-dentin carious lesions, (35.8%) and (31.2%) were the most prevalent phyla, followed by (13.6%), (3.6%), and (2.5%). The microbial composition varied among the individuals, but there were no significant differences in the distribution of the relative microbial abundance between the superficial layers and the deep layers. Although 14.5% of the top 10 taxa were identified as at the genus level, only 25% of the deep-dentin carious samples showed as the most abundant genus. Other abundant taxa included (10.5%), (9.4%), (8.8%), (7.2%), (3.9%), (3.7%), (1.9%), (1.4%), and (1.1%). The most abundant pathway identified in the KEGG database was the metabolic pathway containing 101,427 annotated genes, which consisted of 51.4% of all annotated genes. The carbohydrate metabolism pathway, amino acid metabolism, and membrane transport were the functional traits of the level 2 pathways. These findings suggest that the potent interaction within the microbial communities in deep-dentin carious lesions may play a fundamental role in caries etiology.
龋齿是一种由致龋菌介导、可发酵碳水化合物驱动的动态疾病。牙本质龋的新生态假说认为，微生物群落的改变和特定代谢途径基因的存在，有助于龋病的发生和进展。本研究旨在确定人牙本质深龋病损微生物群落的结构和功能特征。从 8 名 9 至 18 岁患者的第一恒磨牙中获得 16 个牙本质深龋病损。采用 shotgun 宏基因组测序技术，在门、纲、目、科、属和种水平上测量微生物组成和丰度。还对 DNA 测序数据集进行了功能分析，并使用 DIAMOND 软件对不同病变层的京都基因与基因组百科全书数据库进行比较。本研究发现，在牙本质深龋病损中，（35.8%）和（31.2%）是最常见的菌门，其次是（13.6%）、（3.6%）和（2.5%）。微生物组成在个体间存在差异，但在浅层和深层之间，相对微生物丰度的分布没有显著差异。尽管在属水平上有 14.5%的前 10 个分类群被鉴定为，但只有 25%的牙本质深龋样本显示为最丰富的属。其他丰富的类群包括（10.5%）、（9.4%）、（8.8%）、（7.2%）、（3.9%）、（3.7%）、（1.9%）、（1.4%）和（1.1%）。KEGG 数据库中最丰富的途径是包含 101427 个注释基因的代谢途径，占所有注释基因的 51.4%。碳水化合物代谢途径、氨基酸代谢和膜转运是 2 级途径的功能特征。这些发现表明，牙本质深龋病损中微生物群落的强烈相互作用可能在龋病病因学中发挥重要作用。
